Lignans from Gymnema sylvestre

Seven known lignans, tortoside A (1), (+)-syringaresinol (2), (+)-medioresinol (3), (+)-pinoresinol (4), (+)-lyoniresin-6-yl β-D-glucopyranoside (5), (-)-lyoniresinol 3α-O-β-Dglucopyranoside (6), and (-)-lyoniresinol (7) were isolated from the leaves of Gymnema sylvestre (Retz.) R.Br. ex Schult.